Patent EP0363966A2 successfully refreshed from Google Patents.
EP0363966A2
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EP
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Optical head device
Assignee: Sanyo Electric Co Ltd
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Filing: 1989-10-12
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Granted: —
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Expires: 2009-10-12
Abstract
Abstract An optical head device for projecting a light beam on a recording medium (2) to record data thereon or reproduce the recorded data comprises an optical system for forming a beam spot (P) of a specified diameter on the surface of the recording medium, and a transparent contact member (5) disposed at a light emanating portion of the system for the recording medium to come into direct sliding contact therewith. Accordingly, when the contact member moves relative to the recording medium, the dust adhering to the surface of medium is removed by the contact member to assure a recording or reproduction operation free of errors.
Inventors
- 👤 Tsuyoshi Tsujioka
- 👤 Shigeaki Yamamoto
- 👤 Fumio Tatezono
- 👤 Minoru Kume
- 👤 Kotaro Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 03:19
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/002; G11B7/003; G11B7/0031
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
78 words
An optical head device for projecting a light beam on a recording medium to record data thereon or reproduce the recorded data, the device being characterized in that the device comprises an optical system for forming at least one beam spot of a specified diameter on the surface of the recording medium, a transparent contact member being disposed at a light emanating portion of the optical system for the recording medium to come into direct sliding contact therewith.
Claim 2
Dependent Claim
78 words
An optical head device for projecting a light beam on a recording medium to record data thereon or reproduce the recorded data, the device being characterized in that the device comprises an optical system for forming at least one beam spot of a specified diameter on the surface of the recording medium, a transparent contact member being disposed at a light emanating portion of the optical system for the recording medium to come into direct sliding contact therewith.
Claim 3
Dependent Claim
39 words
A device as defined in claim 1 wherein the transparent contact member is disposed on a guide surface for guiding the movement of the recording medium relative to the optical system and is slightly projected from the guide surface.
Claim 4
Dependent Claim
26 words
A device as defined in claim 2 wherein the outer end of the transparent contact member projecting from the guide surface has a smooth curved face.
Claim 5
Dependent Claim
50 words
A device as defined in claim 2 wherein the recording medium is an optical tape, and the guide surface is provided by the outer periphery of a rotary drum, the optical tape being movable along the drum outer periphery as wound around the outer periphery over a predetermined angular range.
Claim 6
Dependent Claim
30 words
A device as defined in claim 1 wherein the transparent contact member is adapted for a beam so as to exhibit a lens effect to converge toward the recording medium.
Claim 7
Dependent Claim
59 words
A device as defined in claim 1 wherein the optical system comprises a convergent lens for converging the light beam toward the recording medium, and the distance between the transparent contact member and the convergent lens is adjustable by shifting means deformable along the optical axis of the convergent lens in accordance with the magnitude of a focus error.
Claim 8
Dependent Claim
56 words
A device as defined in claim 6 wherein the shifting means comprises a piezoelectric element coupled to the convergent lens or the transparent contact member as disposed movably along the optical axis thereof, and a focus control circuit for applying to the piezoelectric element a voltage signal in accordance with the magnitude of the focus error.
Claim 9
Dependent Claim
36 words
A device as defined in claim 1 wherein a reflection preventing film for inhibiting reflection of the light beam is formed on the beam incident face and/or the beam emerging face of the transparent contact member.
Claim 10
Dependent Claim
44 words
A device as defined in claim 1 wherein the transparent contact member is formed of a material having a refractive index equal or approximate to the refractive index of the surface layer of the recording medium to be opposed to the transparent contact member.
Claim 11
Dependent Claim
19 words
A device as defined in claim 1 wherein the transparent contact member is formed of a nonlinear optical material.
Claim 12
Dependent Claim
39 words
A device as defined in claim 1 wherein the recording medium is an optical tape, and the optical tape is formed with a light-transmitting hard film over the surface layer thereof to be opposed to the transparent contact member.
References Cited (Backward Citations)
No citation records indexed.
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